During World War I, he was awarded a prize by the Committee on National Preparedness in 1917 for his poster "Fill the Breach." The next year, he designed naval camouflage under the direction of William Mackay, Chief of the New York District Emergency Fleet Corporation.[3][2]

In 1930, the General Motors selected McClelland Barclay's 'Fisher Body Girl' for a series of advertisements, and she quickly became as popular as 'The Gibson Girl' and 'The Christy Girl'. He used his wife, just 19 years old, as the model for the iconic Fisher Autobody image. She later appeared in magazine advertisements and was so well published with her languid body plastered across the country on billboards, that she was recognized wherever she went. He also illustrated advertisements for the A & P, Eaton Paper Company, Elgin Watches, Humming Bird Hosiery, and Lever Brothers, amongst others.[2] His fashionable women for General Motors' "Body by Fisher" advertising campaign made his work recognizable to virtually every magazine reader in the United States. He also illustrated advertisements for Whitman's Chocolates, Texaco, and Camel and Chesterfield brand cigarettes. Because Barclay was known for his illustrations of "striking women," he earned a judging position at the 1935 Miss America pageant.[1]

Barclay was a member of the Art Students League, the Chicago Art Club, the Society of Illustrators, the Association of Arts and Industries, and the Artists Guild.[1]

Barclay did not limit himself to painting. In the late 1930s, Barclay set up a small company to reproduce jewelry and fabricate utilitarian figures for ashtrays, bookends, desk sets, lamps, and other articles for home and office use. These products were fabricated out of cast grey metal with a thick bronze plate finish and they retailed for just a few dollars. it didn't make him much money. He named the company after himself, McClelland Barclay Arts Products Corporation.[2]

In 1944, a year after his death, Barclay was awarded the Art Directors Club Medal, "in recognition of his long and distinguished record in editorial illustration and advertising art and in honor of his devotion and meritorious service to his country as a commissioned officer of the United States Navy." He was also posthumously inducted in the Society of Illustrators' Hall of Fame.[1]

In June 1938, he was appointed Assistant Naval Constructor with the US Naval Reserve. In mid-1940, Barclay prepared experimental camouflage designs for Navy combat aircraft, but evaluation tests revealed that pattern camouflage was of little use for aircraft. Within weeks of the Japaneseattack on Pearl Harbor, Barclay completed the first of many recruiting posters for the Navy.[1]

Navy Relief show poster by McClelland Barclay (1943).

On October 19, 1940, Barclay reported for active duty. He served in the New York Recruiting office, illustrating posters for the next two and a half years. These images would become some of the most recognizable recruiting images of World War II.[1] Barclay was determined to be a front-line combat artist. In March 1943, He told the San Francisco Examiner, "A camera cannot catch the human element of a fight, the sweat and blood and courage our boys expend every time they face the enemy." In 1941 he volunteered for this position, but was rejected. Eventually he would serve in both the Atlantic and Pacific theaters on the USS Arkansas (BB33), USS Pennsylvania (BB38), USS Honolulu (CL48), and the USS Maryland (BB46).[4]

Appointed a Lt. Commander, Barclay worked on further camouflage assignments until July 18, 1943, when he was reported missing. The U.S.S. LST 342 he was aboard was torpedoed in the Solomon Islands.[2] Barclay was on board, sketching and taking photographs.[1]

McClelland Barclay was awarded the Purple Heart Medal posthumously. He was also bestowed the American Defense Service Medal, Fleet Clasp; the Asiatic-Pacific Area Campaign Medal; the American Area Campaign Medal; and the World War II Victory Medal.[1]